When the problem of pollution is becoming more and more serious, electric vehicles and renewable energies are becoming more and more attractive. A pure electric vehicle supplies power to its electric motor using the stored electric energy to drive the vehicle. The pure electric vehicle may use one or more stored electric energy sources. For example, a first electric energy storage source, for example, an energy battery, may be used to supply longer sustaining energy, and a second electric energy storage source, for example, a power battery may be used to supply higher power energy, for e.g., accelerating the vehicle, and so on. A hybrid electric vehicle may combine an internal-combustion engine with an electric motor powered by an energy storage device (such as a traction battery) to drive the vehicle. Such combination may improve the total fuel efficiency by enabling the internal-combustion engine and the electric motor to operate in their respective higher efficiency ranges. For example, the electric motor may have a higher efficiency when starting to accelerate from a stationary state, and the internal-combustion engine may have a higher efficiency during constant engine running (such as running on a highway). Allowing the electric motor to increase the initial acceleration enables the internal-combustion engine in the hybrid vehicle to be smaller and to have a higher fuel efficiency.
In pure electric vehicles supplied by batteries and plug-in hybrid electric vehicles, high energy density batteries can meet the mileage demand with a single charge, if the sizes of the high energy density batteries are properly configured. However, the high energy density batteries of the same size, due to their relatively low power density, may be unable to meet the power demand caused by instantaneous acceleration or climbing, especially in heavy duty applications, which, for example, is particularly obvious in a city bus or truck. To this end, a plurality of energy sources or hybrid energy sources may be used to meet the mileage demand and power demand of the vehicle simultaneously, without needing to increase the size of a single high energy density battery excessively. In the heavy duty electric vehicles, the combination of the high energy density batteries and power batteries may be used as the hybrid energy source, because such kind of power batteries have high power density and longer lifetime. However, when a plurality of energy sources or hybrid energy sources are introduced into the vehicle driving system, the configuration and control between the plurality of energy sources or hybrid energy sources become complicated. A problem to be solved in the industry is how to properly configure and control the plurality of energy sources or hybrid energy sources to enable the vehicle driving system to run efficiently to deal with all kinds of working conditions, and to ensure the security of the entire energy source power supply system and electric vehicle.
Accordingly, it is necessary to provide a system and a method for solving at least one of the problems as mentioned above.